New 3 way project with PLA200-6 planar

PWRRYD

As mentioned in the other thread, I have started a new 3 way project.  The Vifa NE225W-4 woofers will be in separate bass bins.  The PLA200-6 planar drivers and RT1.3WE tweeter will sit on top.  The top enclosure will employ 2 special features.  Firstly they will have 2.5" radius round overs on their vertical sides.  I obtained some 5" diameter card board tubes that I cut in half and will glue to the sides of the enclosures (like I did in my "Trials" project).  Secondly the enclosure panels will be very well damped.  I will adhere pieces of ceramic floor tile to internal panels where appropriate.  I will also fill the cavities formed by the card board tube halves with dried play sand or kitty litter.

I use a product called Sika Pro Select to adhere the tile pieces.  It's actually called a construction sealant.  It is water based so no smell and clean up is soap/water.  When it's cured it is still very pliable.  Here are some pictures of the rear panel.  I didn't cover the entire panel because I needed a spot at the bottom for the Speakon connector.  I applied the Sika to both the MDF and to the backside of the ceramic tile.  There is about 1/8 inch layer of Sika.

PWRRYD

Card board tube half:

Turn2

I'm anxious to see how the cardboard tube works out, as I have a 4"-er set aside for a console cabinet idea. Lengthwise cuts made with a table saw?

PWRRYD

Yes, the cardboard tube cuts clean and easy with the table saw.  With my Trials project I used regular yellow wood glue to attach the cardboard tube to the MDF enclosure (butt joint).  On this project I'm going to cut a notches on the front and back of the box to accept the tube nice and flush.  Maybe even use epoxy this time.  Something like this:

BrannigansLaw

The cardboard tube idea reminds me of the Grimm LS1! Nice project here...

I have done the ceramic/adhesive/mdf sandwich technique you're doing here before and was very pleased with the result; especially for the modest cost. Seemed to work even better with baltic birch. 

Very nice driver complement too, I've come to love the hivi 1.3WE, which I had completely overlooked until reading the positive reviews here. Is the planar you are using NLA? I'm having a hard time finding info about it.

PWRRYD

I purchased the PLA200-6 from Madisound when they had them on sale.  I found this on AliExpress which I'm sure is the exact same product:

https://www.aliexpress.com/item/32850858542.html?spm=a2g0o.productlist.0.0.219e745bqnQrgD&algo_pvid=43a2bf62-2f3e-4378-85e9-c3c4c894316c&algo_expid=43a2bf62-2f3e-4378-85e9-c3c4c894316c-0&btsid=9bca7cfd-b255-4e52-9dae-f07a6d0f5499&ws_ab_test=searchweb0_0%2Csearchweb201602_2%2Csearchweb201603_53

BrannigansLaw

PWRRYD said:

I purchased the PLA200-6 from Madisound when they had them on sale.  I found this on AliExpress which I'm sure is the exact same product:

https://www.aliexpress.com/item/32850858542.html?spm=a2g0o.productlist.0.0.219e745bqnQrgD&algo_pvid=43a2bf62-2f3e-4378-85e9-c3c4c894316c&algo_expid=43a2bf62-2f3e-4378-85e9-c3c4c894316c-0&btsid=9bca7cfd-b255-4e52-9dae-f07a6d0f5499&ws_ab_test=searchweb0_0%2Csearchweb201602_2%2Csearchweb201603_53

thanks, looks interesting. Wonder how the distortion compares to the Neo8 and its variations... I'll definitely follow your project with interest and consider trying one of these!

BrannigansLaw

What is the 'eco-core' in your cutaway view? I'm not familiar with the term/product

Wolf

Meniscus-branded Ultra touch.

PWRRYD

Yes, same basic stuff as UltraTouch, recycled denim (cotton).  Meniscus sells it in a more convenient 1.5" thickness and calls it Eco-core.

PWRRYD

Hopefully I will be able to take some on and off axis frequency response measurements and distortion measurements this coming weekend.  The PLA200-6 driver will only be surface mounted for the first round of measurements.  I want to make sure they are both good and usable before I spend the time and materials to veneer and make a template to flush mount them.

PWRRYD

I got the cardboard tubes glued to the boxes last night.

BrannigansLaw

PWRRYD said:

Yes, same basic stuff as UltraTouch, recycled denim (cotton).  Meniscus sells it in a more convenient 1.5" thickness and calls it Eco-core.

I've looked around and this product seems not to be available in Canada... in general cotton and denim insulation are hard to come by, I'll have to keep looking. Have source sheep wool though

jhollander

BrannigansLaw said:

Have source sheep wool though

Even better for audio

PWRRYD

Didn't someone (Vance D. maybe?) do a test of different stuffing materials for TL's and determined that natural sheep wool was the best? 

jhollander

I think there were several tests of wool. I don't recall Vance doing any testing but he may have referenced it in one of his books.  You need to meet him...

PWRRYD

I need to meet Vance?

jhollander

Oh yeah  

PWRRYD

Next up is to cut some semi-circles to cap off the side wings and fill them full of sand.

jhollander

Sorry for the hijack...We got to experience from 2:00 to 3:00 of this track from Vance  https://www.youtube.com/watch?v=n4Bb7p9gggc

Wolf

Why not glue a top and bottom on and flush-trim?

PWRRYD

Yes there will hardwood tops and bottoms glued on, flush trimmed, and the top will have 3/4" round overs.  I already have the hardwood board.  I want the structure as you see it now independant of the top and bottom hardwood.  You'll see why when I get to the veneer and finishing stages.  And as Forest Gump says "that's all I have to say about that". 

PWRRYD

PWRRYD

PWRRYD

PWRRYD

Next up....  fill them with sun dried pool filter sand.  Should add about 10 pounds each!

Wolf

I still want to do a 2-way in that kind of form factor, whether faceted or rounded and what drivers is still yet to be determined.
So- did you run the circles through the table saw with a jig, or use the miter saw with a jig? Or what?

4thtry

Cool project.  Those big round-overs should help to smooth out diffraction ripple significantly.  You mentioned that the top edge will have a 3/4" radius round-over.  When laying out the design, did you consider putting an additional piece of 2.5" radius material along the top edge as well?  Or would that have been an almost impossible thing to do?  Just wondering.     

Wolf

Thank you, Bill! You just gave me a great idea....

PWRRYD

I made those circles with my router.  I just measured to the inside of the cutter instead of the outside.  Super easy.

Wolf

Not what I meant. I meant the diameter cut across them.